Does Geographic Region Impact the Efficacy of Ezogabine/Retigabine in Adults with Partial-Onset Seizures? Analysis of US vs Non-US Results (P06.123)

Objective: To evaluate whether the efficacy of ezogabine/retigabine (EZG/RTG) as adjunctive treatment for adults with partial-onset seizures varies by geographic region (US vs non-US). Background EZG/RTG (600, 900, 1200mg/day) is effective and generally tolerated as adjunctive therapy in adults with partial-onset seizures. Design/Methods: Post-hoc analyses were conducted using the integrated data from three double-blind, placebo-controlled trials (Studies 205, 301 [NCT00232596], 302 [NCT00235755]) to evaluate differences between US and non-US subjects in responder rate (≥50% reduction in seizure frequency) and in percent change in 28-day total partial-seizure frequency from baseline to double-blind phase. The EZG/RTG 1200mg/day group and the overall EZG/RTG group (600, 900, 1200mg/day combined) were compared with appropriate corresponding placebo groups. Results:EZG/RTG 1200mg/day: There was a significant difference between EZG/RTG and placebo in percent change in 28-day total partial-seizure frequency for both US (median: EZG/RTG [n=82], −34.8 vs placebo [n=76], −22.7; p=0.039) and non-US subjects (median: EZG/RTG [n=175], −39.3 vs placebo [n=170], −12.3; p 0.3). Overall EZG/RTG: The difference in percent change in 28-day total partial seizure frequency between EZG/RTG and placebo demonstrated a strong trend for US patients (median: EZG/RTG [n=99,] –35.7 vs placebo [n=76], –22.7; p=0.055) and was significant for non-US subjects (median: EZG/RTG [n=706], −32.6 vs placebo [n=346], –13.4; p 0.4). Conclusions: EZG/RTG, as adjunctive treatment in adults with drug-resistant partial-onset seizures, demonstrated efficacy in both US and non-US regions. Supported by: Valeant Pharmaceuticals International and GlaxoSmithKline. Disclosure: Dr. Burdette has received personal compensation for activities with GlaxoSmithKline, Inc. and UCB Pharma. Dr. Burdette has received research support from GlaxoSmithKline, Inc. Dr. Gil-Nagel has received personal compensation for activities with Bial, Eisai Inc., GlaxoSmithKline, Inc., UCB Pharma and Medtronic as a speaker and/or consultant. Dr. Gil-Nagel has received research support from UCB Pharma. Dr. Scott has received personal compensation for activities with Valeant Pharmaceuticals and GlaxoSmithKline. Dr. Scott holds stock and/or stock options in GlaxoSmithKline. Dr. Lee has received personal compensation for activities with GlaxoSmithKline as an employee. Dr. Lee holds stock and/or stock options in GlaxoSmithKline. Ms. McDonald has received personal compensation for activities with GlaxoSmithKline as an employee. Ms. McDonald holds stock and/or stock options inGlaxoSmithKline. Dr. DeRossett has received personal compensation for activities with GlaxoSmithKline as an employee.Dr. DeRossett holds stock and/or stock options in GlaxoSmithKline.